Balanced Binary Tree

Given a binary tree, determine if it is height-balanced.

For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of everynode never differ by more than 1.

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    bool isBalancedNew(TreeNode *root, int & height){
        if (!root){
            height = 0;
            return true;
        }
        int left_height = 0, right_height = 0;
        bool left_flag = isBalancedNew(root->left,left_height);
        bool right_flag = isBalancedNew(root->right,right_height);
        height = max(left_height,right_height) + 1;
        return left_flag && right_flag && abs(left_height - right_height) <= 1;
    }
    bool isBalanced(TreeNode *root) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        int height = 0;
        return isBalancedNew(root,height);
    }
};